objective-c - 无法从 Objective-C 调用 Swift 函数

Question

我想在 Objective-C 中调用 Swift 类中的这个静态函数:

static internal func photoActionSheet<T:UIViewController where T:UIImagePickerControllerDelegate, T:UINavigationControllerDelegate>(hostAndDelegateViewController:T)

我可以从 ObjC 调用该类中的其他函数，但它不知道只有这个函数

谢谢

Answer 1

具有通用类型约束的函数无法导出到 Objective-C。

作为解决方法，您可以像下面这样定义函数并检查函数实现中的协议(protocol)一致性:

static internal func photoActionSheet(hostAndDelegateViewController: UIViewController) {
  guard let vc = hostAndDelegateViewController as? protocol<UINavigationControllerDelegate, UIImagePickerControllerDelegate> else {
    fatalError("hostAndDelegateViewController must conform UINavigationControllerDelegate and UIImagePickerControllerDelegate")
  }

  // let picker = UIImagePickerController()
  // picker.delegate = vc
}

同样，Objective-C 类型 UIViewController<UIImagePickerControllerDelegate, UINavigationControllerDelegate> *将作为 UIViewController! 导出到 Swift